The present invention relates to a device and a method for analyzing waveform propagation of a digital signal in a circuit based on circuit diagram information or the like, and a computer-readable recording medium recorded with a program for making a computer execute the method according to the present invention.
FIG. 16 is a diagram showing a structure and a data flow of a conventional circuit analyzing device. This circuit analyzing device includes a circuit diagram information generating section 81 for supporting preparation of a circuit diagram and for generating circuit diagram information (information on a circuit diagram) D81, a layout pattern information generating section 82 for generating layout pattern information (information on a layout pattern) of this circuit, and an element information extracting section 83 for extracting element information (information on a circuit element and a parasitic element) D82 from the layout pattern generated by the layout pattern information generating section 82.
Further, this circuit analyzing device includes a circuit connection information extracting section 84 for extracting net list information (circuit connection information) D83 of the whole circuit, based on the circuit diagram information D81 generated by the circuit diagram information generating section 81 or the element information D82 extracted by the element information extracting section 83, a circuit simulation section 85 for simulating the analysis of a transient response of a circuit using the net list information D83 extracted by the circuit connection information extracting section 84, and a waveform display section 86 for displaying a waveform of a result of the analysis of the circuit simulation section 85.
FIG. 17 is a flowchart showing a flow of the operation of the conventional circuit analyzing device. First, the circuit diagram information generating section 81 generates the circuit diagram information D81 or the layout pattern information generating section 82 generates the layout pattern information, and the element information extracting section 83 extracts the element information D82 (S81). Subsequently, the circuit connection information extracting section 84 extracts the net list information D83 from the circuit diagram information D81 or from the element information D82 (S82). Subsequently, the circuit simulation section 85 simulates the analysis of a transient response of a circuit using the net list information D83 (S83). Subsequently, the waveform display section 86 displays a waveform of a result of the analysis (S84). A user visually observes this waveform, and confirms the whole wiring to see whether there is a problem or not in the waveform propagation characteristics of the digital signal (S85).
In the conventional circuit analyzing device, however, a simulation is carried out for the whole circuit, and the user visually observes the waveform of a result of the analysis, and confirms whether there is a problem or not in the waveform propagation characteristics of the digital signal. Therefore, there has been a problem that there is a reduction in the reliability in the decision made on the waveform propagation characteristics of each wiring of the circuit. Further, there has been a problem that substantial time and labor are required for analyzing the circuit.
It is an object of this invention to provide, a device and a method for analyzing a circuit that can improve the reliability in the decision made on the waveform propagation characteristics of each wiring of the circuit and that can decrease the time and labor required for analyzing the circuit, and a computer-readable recording medium recorded with a program for making a computer execute the method according to the present invention.
According to one aspect of this invention, there is provided a circuit analyzing device comprising a wiring model information generating unit for generating wiring model information for each wiring of a circuit; and an analyzing unit for analyzing waveform propagation characteristics of each wiring model information that has been generated by the wiring model information generating unit. The wiring model information generating unit generates wiring model information for each wiring of a circuit, and the analyzing unit analyzes waveform propagation characteristics of each wiring model information that has been generated by the wiring model information generating unit. Therefore, it is possible to obtain quantitative information for making a decision, and it becomes easily possible to make a secure decision for each wiring.
Further, the wiring model information generating unit generates the wiring model information including LC circuit parasitic and RC circuit parasitic information based on layout information of the circuit. Therefore, it is possible to carry out a more suitable analysis particularly in the case of analyzing a circuit that processes a high-frequency digital signal of 1 GHz or above.
Further, the analyzing unit analyzes spectrum characteristics and/or S parameter characteristics. Therefore, it is possible to carry out a more detailed analysis.
Further, a deciding unit is provided for automatically deciding on whether each wiring is bad or good in waveform propagation, based on a result of the analysis of the analyzing unit. The deciding unit automatically decides whether each wiring is bad or good in waveform propagation. Therefore, it is more easily possible to make a secure decision on good or bad of each wiring.
Further, a correction circuit information generating unit is provided for generating correction circuit information on a correction circuit having an element for correcting waveform propagation characteristics added to a wiring that has been decided as bad by the deciding unit. The correction circuit information generating unit generates correction circuit information on a correction circuit having an element for correcting waveform propagation characteristics added to a wiring that has been decided as bad by the deciding unit. Therefore, it is possible to automatically correct the waveform propagation characteristics of the bad wiring.
Further, a layout information generating unit is provided for generating layout information of the correction circuit, based on the correction circuit information that has been generated by the correction circuit information generating unit, wherein the wiring model information generating unit generates wiring model information for each wiring of the correction circuit including LC circuit parasitic and RC circuit parasitic information, based on the layout information that has been generated by the layout information generating unit. Therefore, it is possible to obtain an optimum circuit by repeatedly carrying out the analysis of the correction circuit until when there is no bad wiring.
Further, an assigning unit is provided for assigning a part of a circuit as a part to be analyzed. The wiring model information generating unit generates wiring model information for only a part of the circuit that has been assigned by this assigning unit. Therefore, it is possible to further decrease the time required for analyzing the circuit.
According to another aspect of this invention, there is provided a circuit analyzing method comprising a wiring model information generating step for generating wiring model information for each wiring of a circuit; and an analysis step for analyzing waveform propagation characteristics of each wiring model information that has been generated at the wiring model information generating step. At the wiring model information generating step, wiring model information is generated for each wiring of a circuit, and at the analysis step, waveform propagation characteristics are analyzed for each wiring model information that has been generated at the wiring model information generating step. Therefore, it is possible to obtain quantitative information for making a decision, and it becomes easily possible to make a secure decision for each wiring.
Further, at the wiring model information generating step, the wiring model information including LC circuit parasitic and RC circuit parasitic information is generated based on layout information of the circuit. Therefore, it is possible to carry out a more suitable analysis particularly in the case of analyzing a circuit that processes a high-frequency digital signal of 1 GHz or above.
Further, at the analysis step, spectrum characteristics and/or S parameter characteristics are analyzed. Therefore, it is possible to carry out a more detailed analysis.
Further, a decision step is provided for automatically deciding on whether each wiring is bad or good in waveform propagation, based on a result of the analysis at the analysis step. Thus, at the decision step, whether each wiring is bad or good in waveform propagation is automatically decided based on a result of the analysis at the analysis step. Therefore, it is easily possible to make a more secure decision on good or bad of each wiring.
Further, a correction circuit information generating step is provided for generating correction circuit information on a correction circuit having an element for correcting waveform propagation characteristics added to a wiring that has been decided as bad at the decision step. Thus, at the correction circuit information generating step, there is generated correction circuit information on a correction circuit having an element for correcting waveform propagation characteristics added to a wiring that has been decided as bad at the decision step. Therefore, it is possible to automatically correct the waveform propagation characteristics of the bad wiring.
Further, a layout information generating step is provided for generating layout information of the correction circuit, based on the correction circuit information that has been generated at the correction circuit information generating step. At the wiring model information generating step, there is generated wiring model information for each wiring of the correction circuit including LC circuit parasitic and RC circuit parasitic information, based on the layout information that has been generated at the layout information generating step. Therefore, it is possible to obtain an optimum circuit by repeatedly carrying out the analysis of the correction circuit until when there is no bad wiring.
Further, an assignment step is provided for assigning a part of a circuit as a part to be analyzed. At the wiring model information generating step, wiring model information is generated for only a part of the circuit that has been assigned at the assignment step. Therefore, it is possible to further decrease the time required for analyzing the circuit.
According to still another aspect of this invention, there is provided a computer-readable recording medium that is recorded with a program for making a computer execute any one of the above-described methods according to this invention. Therefore, the program can be read by the computer, and it becomes possible to execute the operation of the methods of the above-described aspects by the computer.
In this case, the xe2x80x9ccomputer-readable recording mediumxe2x80x9d includes a xe2x80x9cportable physical mediumxe2x80x9d such as a magnetic disk like a floppy disk, a semiconductor memory (including that incorporated in a cartridge or a PC card) like a ROM, an EPROM, an EEPROM, a flash ROM, etc., an optical disk like a CD-ROM, a DVD, etc., an optical magnetic disk like an MO, etc., and a xe2x80x9cfixed physical mediumxe2x80x9d like a ROM, a RAM, a hard disk, etc. that are incorporated in various types of computer systems.
Further, the xe2x80x9ccomputer-readable recording mediumxe2x80x9d may also include a communication medium for short-time holding a program like a communication line for transmitting a program via a network like a LAN, a WAN, Internet, etc. The xe2x80x9cprogramxe2x80x9d is a one that describes a data processing method. A language to be described and a describing method are not particularly limited, and formats of a source code, a binary code and an execution format are not limited. Further, the xe2x80x9cprogramxe2x80x9d is not necessarily limited to a one formed in a single structure, but also includes a distributed structure as a plurality of modules and libraries, and a program that achieves its function in co-operation with separate programs of an OS and the like.